Degree Type


Date of Award


Degree Name

Doctor of Philosophy




A cost minimizing linear programming model was developed to determine the minimum cost of supplying hardwood lumber, veneer and plywood, and particleboard in each year of the period 1990 to 2030;The continental United States was divided into nine supply and three demand regions. Production, export, import and transportation activities were defined for demand regions. The total cost of producing, transporting, and importing the products was minimized subject to regional and national demand (consumption, export, and import) and resource (land, labor, and capital) constraints;The minimum costs (in 1972 dollars) of supplying the products in the years 1990, 2010 and 2030 were found to be 4709 million, 5852 million, and 7264 million, respectively. Labor and capital resources required in the cost minimization were found to be limiting in some regions while land is available in sufficient quantity in all regions;Sensitivity tests performed on optimal solutions indicate the model is responsive to changes in costs and in budget constraints. For instance, an increase in the budget constraints across all regions increased the production level of the supply regions. Also, an increase in the budget constraints, of the demand regions only, increased their productive capacity;The introduction of export cost, which was previously not defined in the model, caused no changes in export quantities. Increasing the import costs resulted in an increase in domestic production and stopped products imports in all regions. Simultaneous increases of export and import costs and of the budget constraint resulted in increases in domestic production across all regions, a decline in the quantity of product transportation from supply to demand regions, a cessation of imports, and left the export unchanged;Regions with high potential to produce and transport products to demand regions were found to be Middle Atlantic and Central States. Also, export requirements in supply regions were first met before transportation to demand regions and that cost is best minimized through domestic production rather than imports of two (lumber and particleboard) of the four hardwood products.



Digital Repository @ Iowa State University,

Copyright Owner

Francis Nwonwu



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198 pages